Burner

ABSTRACT

An improved compact liquid fuel burner is described wherein vaporized liquid fuel mixed with combustion gases and an airstream is supplied to the lateral side of a cylindrical burner structure in a lateral plane. An additional stream of air is supplied directly to the fire chamber in the burner in the vicinity of the lateral plane to enhance combustion of the vaporized fuel. A combustion gas feedback conduit is coaxially located in an end of the chamber in the vicinity of the entry port of the vaporized fuel to supply heat to a vaporization chamber for gassification of the liquid fuel. A venturi is employed to draw the vaporized fuel into an airstream for combustion in the fire chamber. The burner may be alternatively fueled by gas.

United States Patent [72] Inventor Robert Relchhelm Lancaster, Pa. [2]] Appl. No. 56,482 [22] Filed July 20, 1970 [45] Patented Jan. 4, 1972 [73] Assignee Burnham Corporation lrvington-on-Hudson, N.Y.

[54] BURNER 16 Claims, 2 Drawing Figs.

[52] US. Cl 431/116, 431/207 [51] Int. Cl F23d 11/46 [50] Field of Search 431/207, 217, 116, ll

[56] References Cited UNITED STATES PATENTS 2,735,481 2/1956 Reichhelm 431/217 X 3,277,945 10/1966 Vermes 431/ll6X Primary ExaminerEdward G. Favors Attorney-Bryan, Parmelee, Johnson & Bollinger ABSTRACT: An improved compact liquid fuel burner is described wherein vaporized liquid fuel mixed with combustion gases and an airstream is supplied to the lateral side of a cylindrical burner structure in a lateral plane. An additional stream of air is supplied directly to the tire chamber in the burner in the vicinity of the lateral plane to enhance combustion of the vaporized fuel. A combustion gas feedback conduit is coaxially located in an end of the chamber in the vicinity of the entry port of the vaporized fuel to supply heat to a vaporization chamber for gassification of the liquid fuel. A venturi is employed to draw the vaporized fuel into an airstream for combustion in the tire chamber. The burner may be alternatively fueled by gas.

VENTUR/ 550 7 m m/20R BURNER BACKGROUND OF THE INVENTION This invention relates to an improved burner. More specifically this invention relates to an improved burner utilizing an evaporator for gassifying a liquid fuel.

In U.S. Pat. N0. 3,361,183, I describe a burner which utilizes a gassifier to evaporate liquid fuel which is combusted in the burner. As described in that patent, a tapered fire chamber is formed in a burner body and terminates at an enlarged unimpeded outlet port at one end and is provided with evaporated fuel at the other opposite end. At a location near the outlet port a feedback conduit is exposed to the combustion gases and connected to a chamber in which it is mixed with liquid fuel to gassify the fuel. A source of pressurized air is supplied to the other end of the fire chamber through a venturi operatively coupled to the gassifying chamber for drawing evaporated fuel from the gassifying chamber and mixing it with the supply of air for burning at said opposite end of the fire chamber.

SUMMARY OF THE INVENTION In accordance with the present invention a compact burner structure is provided, with excellent fuel-burning efiiciency, by vaporizing fuel and supplying the evaporated fuel, mixed with air and combustion gas, to one side of the fire chamber of the burner. A combustion gas feedback conduit is located at the end of the fire chamber to supply heated gases to a liquid fuel gassifying chamber. Pressurized air is also supplied directly to the fire chamber to enhance combustion of the evaporated fuel.

An advantage of a burner constructed in accordance with the invention resides in its compact size and its reliable ignition. The side feeding of fuel precisely locates the burner flame generally to the rear of the fire chamber and creates turbulence for efficient combustion. The combustion feedback conduit is advantageously located adjacent the flame region in the burner to efficiently provide a large amount of heat to the evaporation chamber.

BRIEF DESCRIPTION OF DRAWINGS The invention will be understood from the following description in conjunction with the drawings wherein FIG. 1 is a schematic representation of a burner and its control elements; and

FIG. 2 is a perspective view of a burner constructed in accordance with the invention.

DETAILED DESCRIPTION In the burner schematically illustrated in FIG. 1 liquid fuel, such as -No. l or No. 2 fuel oil, is burned while in the evaporated state. Beat for the evaporation of the fuel is drawn from the burner. City-type gas, natural gas, LP gases, propane and butane may be employed as fuel for the burner.

FIG. 1 shows a schematic view of my burner structure 10. This is a cylindrical burner 12 having a fire chamber 14 in which evaporated fuel is burned. The fire chamber has an outlet port 15 for exhaust gases at one end. Outlet port 15 is formed in an annular wall 19 of the burner 14 and of reduced diameter relative to the diameter of the fire chamber 14 to build up a back pressure in the flame region of the burner 12 for enhanced combustion. The burner 12 discharges the combustion gases axially in the direction of arrow 16 for heating purposes and then to a vent or flue (not shown).

Air enters through inlet pipe 17, drawn by a compressor 18, such as a blower or the like, for pressurization within a selected operating range. The pressurized air is supplied to pressure differential generator 20 such as the input of a venturi. The pressure differential generator has a low-pressure input 22 connected to a liquid fuel evaporator 24. Evaporator 24 has one input 26 coupled to a supply of fuel such as oil and another input 28 coupled to a combustion gas feedback conduit 30. Conduit 30 is in gas flow communication with an end 32 of the tire chamber 14 at a port 33. The output of the differential pressure generator 20 is supplied to a laterally located side port 34 of the fire chamber 14 in the vicinity of the fire chamber end 32. Pressurized air from compressor 18 is directly supplied to the burner 12 through a conduit 36 which terminates at a port 38 located generally in a lateral side plane 39 near the port 34. A sparkplug 41 is located also in the vicinity of the circumferential radial plane 39.

The gas pressure difi'erential generator 20 further is provided with an inlet port 40 in communication with a supply of city gas or the like through a solenoid valve 42. A solenoid valve 44 is located in series with the fuel line so that the burner 12 may be operated, as desired, on liquid fuel or gas.

The operation of the burner 12 may best be explained with reference to FIG. 2 wherein the several components are shown in perspective. The air compressor 18 is actuated to supply pressurized air both to venturi 20 and directly to the cylindrical fire chamber 14 through conduit 36. The compressor is sized to provide adequate air pressure needed to overcome the back pressure in the fire chamber 14 while maintaining negative pressure in the gassification chamber 24. Compressor 18 provides relatively high pressure at low volumes.

The vaporizer 24 is initially heated by an electric heater mounted in the vaporizer 24 and supplied with electric power on leads 25. The vaporizer 24 is heated to the desired temperature needed for gassification of the liquid fuel. This temperature is selected sufi'iciently high to overcome heat losses but not so high as to crack the oil. Generally temperature of the combustion gases entering the vaporizer are from 800 to l,000 F. and the vaporized fuel gases are delivered to venturi 20 at temperatures generally above 650 F.

When liquid gassification occurs the venturi, which causes a pressure reduction in the vaporization chamber 24, sucks vaporized fuel through conduit 46 to the venturi 20. The vaporized fuel is passed with the gas stream from the compressor 18 through output conduit 48 to a radial side of the cylindrically shaped burner 12. Igniter 41, being located in a radial plane 39, is actuated and burning commences.

It is to be noted that the mixture of fuel-combustion gases and air from port 34 is ejected into the fire chamber 14 and directed at an opposite wall, and not toward exhaust outlet 15. The mixture thus is forced to turn back and slows down sufficiently for igniter sparkplug 41 to obtain reliable fuel ignition. This ignition is generally independent of pressure in the sense that the fire chamber region around the radial plane 39 contains a slow moving fuel mixture which is reliably ignited.

The combustion takes place in a flame region in the fire chamber near the rear end 32 thereof in the vicinity of a feedback port 33 which is coaxially aligned with the fire chamber 14. The hot gases in the chamber are mostly exhausted from the open end of the fire chamber, but a small amount, of the order of 5 percent, including flames is sucked back through conduit 30 to the vaporization chamber 24. This feedback of gases and flames is enhanced by the low pressure prevailing in the evaporating chamber 24 and assures quick and reliable fuel vaporization.

The feedback hot combustion gases heat the liquid fuel to the desired vaporization temperature and are thoroughly mixed with the fuel when the vaporized fuel mixture reaches the venturi 20. At the venturi the vaporized fuel is swept along with the flow of air from the compressor 18 to the burner 12 for combustion. The directly supplied air from port 38 located in the vicinity of radialplane 39 assures complete combustion of the fuel.

The side feeding of the fuel to the flame region enhances turbulence in the burner 12 thus retaining fuel mixtures for complete fuel combustion as well as advantageous feedback of hot combustion gases to the vaporizer. The turbulent burning in the fire chamber permits the axial reduction of the fire chamber length without deleterious efiects. The pressure in the fire chamber may increase to some extent, but this is compensated for by supplying pressurized air from compressor 18 at a sufficiently high pressure to maintain a negative pressure in conduit 46.

Satisfactory operation is obtained with an operating pressure in the conduit 50 between compressor 18 and venturi 20 at 18 or 20 inches of water. These pressures do not define operational limitations. In fact higher pressures for heavier fuels may be employed. Too high a pressure in conduit 50 causes too much fuel to be drawn. The pressures are selected on the basis of factors such as pressure drop across the venturi and back pressure in the exhaust outlet.

In a burner made in accordance with the invention the diameter of the fire chamber 14 was about 5 inches and the axial length about 8 inches. The port 15 had a diameter of about 2 inches. The feedback conduit 30 was made as short as practicable, of about 2 to 3 inches in length, and the conduit 46 was about 6 inches long to preserve the fuel in its vaporized state and prevent its condensation.

An advantageous feature of the burner 10 of the invention makes use of the high gas pressures employed in the burner 10 by preheating of the air drawn by compressor 18. Exhaust gases from outlet port are passed to a flue conduit 60 which is passed through a larger inlet duct 62. Inlet duct 62 is shown coupled to the inlet conduit 17 to allow compressor 18 to draw in air that is preheated as the result of heat exchange with exhaust gases in conduit 60. The preheated inlet air enhances combustion efficiency of the burner.

The burner 10 may be operated with ordinary city gas, natural gas, LP gases, propane and butane supplied along an input conduit 64 through solenoid valve 42. In such case solenoid valve 44 in series with the liquid fuel line is closed and solenoid valve 42 is opened. Gas in conduit 64 is sucked into conduit 48 by venturi 20 together with hot combustion gases from feedback conduits 30 and 46. The gas is thus advantageously supplied to the fire chamber 14 at an elevated temperature for efficient combustion in the burner.

Having thus described a compact burner for use with gas or liquid fuel the many advantages may be understood. The burning vaporized fuel occurs with a shorter flame length allowing an advantageous reduction in the length of the burner. The higher pressures in the fire chamber permits the use of a smaller diameter chimney tube which in fact may then be passed in heat exchange relationship with the air drawn by the compressor for air preheating. The burner is sufficiently compact to function as a space heater.

What is claimed is:

1. In a burner utilizing an evaporation chamber connected to a supply of liquid fuel, a combustion gas feedback conduit for supplying heated combustion gases to the evaporation chamber to heat the liquid fuel above its evaporation temperature, and a supply of pressurized air coupled to the burner through a pressure differential generator operatively coupled to the evaporation chamber to extract evaporated fuel therefrom for mixture with and transmittal to the burner with the supply of pressurized gas, the improvement comprising a burner having a fire chamber aligned with a desired axis for the removal of gases at one axial end of the fire chamber, said fire chamber having an evaporated fuel inlet port in a lateral side in the vicinity of the other axial end of the fire chamber, said evaporated fuel inlet port being in communication with the mixture of evaporated fuel and air from the pressure differential generator, said burner fire chamber further having a feedback port located in the vicinity of the evaporate fuel inlet port and in communication with the combustion gas feedback conduit, and means for supplying pressurized air directly to the fire chamber in the vicinity of the evaporated fuel inlet port to enhance fuel combustion whereby a compact efficient heat-generating burner is formed.

2. The improved burner as claimed in claim 1 wherein the means for supplying pressurized air directly to the fire chamber introduces said air generally in the same lateral plane of the evaporated fuel inlet port.

3. The improved burner as claimed in claim 1 wherein said burner is substantially cylindrical with said feedback port being coaxially located in the other end of the fire chamber and with said evaporated fuel inlet port located generally diametrically opposite said directly supplied pressurized air.

4. The improved burner as claimed in claim 1 wherein the feedback port is located behind the flame region of the burner on the side opposite of said one axial end of the burner where the combustion gases are removed.

5. The improved burner as claimed in claim 4 wherein said feedback port is located in an end of the fire chamber axially opposite of the one axial end of the burner where the combustion gases are removed.

6. The improved burner as claimed in claim 4 wherein the one axial end of the burner where the combustion gases are removed is provided with an apertured wall across the fire chamber with the aperture in the wall of substantially smaller cross section then the cross section of the fire chamber.

7. The improved burner as claimed in claim 6 wherein the fire chamber is cylindrical in cross section with the wall aperture coaxially located.

8. The improved burner as claimed in claim 7 wherein said feedback port is coaxially located at the other axial end of the burner.

9. In a burner utilizing a fire chamber connected to a supply of fuel from a pressure differential generator with a combustion gas feedback conduit for supplying heated combustion gases to the pressure differential generator to heat the fuel and a supply of pressurized air applied to the pressure differential generator to deliver a fuel and air mixture to the fire chamber. the improvement comprising a burner having a fire chamber, said fire chamber terminating at an apertured front located wall, said wall having an exhaust gas outlet aperture selected to increase the back pressure in the fire chamber during burning operation, said fire chamber having a fuel inlet port located in a lateral side, an igniter generally located near the lateral plane in which the fuel inlet port is located, said feedback conduit being located to pass hot combustion gases from the rear of the fire chamber to the fuel mixture supplied by the differential pressure generator to the inlet port and means for supplying pressurized air directly to the fire chamber in the vicinity of the fuel inlet port to enhance fuel combustion whereby a compact efficient heatgenerating burner is formed.

10. The improved burner as claimed in claim 9 and further including an evaporation chamber located in series with the feedback conduit and means for supplying liquid fuel to the evaporation chamber for gassification therein.

1 l. The improved burner as claimed in claim 10 and further including means for supplying fuel gas to the pressure differential generator, and valve means for alternately selectively delivering fuel gas or liquid fuel to the burner.

12. The improved burner as claimed in claim 11 wherein said valve means if formed of a pairv of solenoid valves respectively operatively placed in series with he liquid fuel and fuelgas-supplying means.

13. The improved burner as claimed in claim 9 wherein said burner fire chamber is cylindrical with said feedback conduit commencing at a coaxially located feedback port in the rear of the fire chamber.

14. The improved burner as claimed in claim 9 wherein said direct-air-supplying means supplies air to the region of the fire chamber adjacent the lateral plane in which the fuel inlet port is located.

15. In a burner utilizing a fire chamber connected to a supply of fuel mixture from a pressure differential generator, a combustion gas feedback conduit for supplying heated combustion gases to the pressure differential generator to heat the fuel and a supply of pressurized air being applied to the pressure differential generator to deliver a fuel and air mixture to the fire chamber, the improvement comprising a burner having a fire chamber, said fire chamber terminating at an apertured front located wall, said wall having an exhaust gas outlet aperture sized to increase the back pressure in the fire chamber during burning operation, said fire chamber having a fuel inlet port located in a lateral side towards the rear of the chamber in a lateral plane to define a flame region in the rear of the fire chamber including the lateral plane,

said feedback conduit being located to pass hot combustion gases from the rear of the flame region to the pressure differential generator for heating of fuel and means for supplying pressurized air directly to the fire chamber in the vicinity of the flame region and fuel inlet port to enhance fuel combustion and means located generally in the vicinity of the lateral plane to ignite the fuel.

16. The improved burner as claimed in claim 15 and further including flue means for passing exhaust gases from the outlet aperture in heat exchange relationship with the air being supplied to the burner for preheating thereof. 

1. In a burner utilizing an evaporation chamber connected to a supply of liquid fuel, a combustion gas feedbacK conduit for supplying heated combustion gases to the evaporation chamber to heat the liquid fuel above its evaporation temperature, and a supply of pressurized air coupled to the burner through a pressure differential generator operatively coupled to the evaporation chamber to extract evaporated fuel therefrom for mixture with and transmittal to the burner with the supply of pressurized gas, the improvement comprising a burner having a fire chamber aligned with a desired axis for the removal of gases at one axial end of the fire chamber, said fire chamber having an evaporated fuel inlet port in a lateral side in the vicinity of the other axial end of the fire chamber, said evaporated fuel inlet port being in communication with the mixture of evaporated fuel and air from the pressure differential generator, said burner fire chamber further having a feedback port located in the vicinity of the evaporate fuel inlet port and in communication with the combustion gas feedback conduit, and means for supplying pressurized air directly to the fire chamber in the vicinity of the evaporated fuel inlet port to enhance fuel combustion whereby a compact efficient heat-generating burner is formed.
 2. The improved burner as claimed in claim 1 wherein the means for supplying pressurized air directly to the fire chamber introduces said air generally in the same lateral plane of the evaporated fuel inlet port.
 3. The improved burner as claimed in claim 1 wherein said burner is substantially cylindrical with said feedback port being coaxially located in the other end of the fire chamber and with said evaporated fuel inlet port located generally diametrically opposite said directly supplied pressurized air.
 4. The improved burner as claimed in claim 1 wherein the feedback port is located behind the flame region of the burner on the side opposite of said one axial end of the burner where the combustion gases are removed.
 5. The improved burner as claimed in claim 4 wherein said feedback port is located in an end of the fire chamber axially opposite of the one axial end of the burner where the combustion gases are removed.
 6. The improved burner as claimed in claim 4 wherein the one axial end of the burner where the combustion gases are removed is provided with an apertured wall across the fire chamber with the aperture in the wall of substantially smaller cross section than the cross section of the fire chamber.
 7. The improved burner as claimed in claim 6 wherein the fire chamber is cylindrical in cross section with the wall aperture coaxially located.
 8. The improved burner as claimed in claim 7 wherein said feedback port is coaxially located at the other axial end of the burner.
 9. In a burner utilizing a fire chamber connected to a supply of fuel from a pressure differential generator with a combustion gas feedback conduit for supplying heated combustion gases to the pressure differential generator to heat the fuel and a supply of pressurized air applied to the pressure differential generator to deliver a fuel and air mixture to the fire chamber, the improvement comprising a burner having a fire chamber, said fire chamber terminating at an apertured front located wall, said wall having an exhaust gas outlet aperture selected to increase the back pressure in the fire chamber during burning operation, said fire chamber having a fuel inlet port located in a lateral side, an igniter generally located near the lateral plane in which the fuel inlet port is located, said feedback conduit being located to pass hot combustion gases from the rear of the fire chamber to the fuel mixture supplied by the differential pressure generator to the inlet port and means for supplying pressurized air directly to the fire chamber in the vicinity of the fuel inlet port to enhance fuel combustion whereby a compact efficient heat-generating burner is formed.
 10. The improved burner as claimed in claim 9 and further including an evaporation chamber located in series with tHe feedback conduit and means for supplying liquid fuel to the evaporation chamber for gassification therein.
 11. The improved burner as claimed in claim 10 and further including means for supplying fuel gas to the pressure differential generator, and valve means for alternately selectively delivering fuel gas or liquid fuel to the burner.
 12. The improved burner as claimed in claim 11 wherein said valve means is formed of a pair of solenoid valves respectively operatively placed in series with he liquid fuel and fuel-gas-supplying means.
 13. The improved burner as claimed in claim 9 wherein said burner fire chamber is cylindrical with said feedback conduit commencing at a coaxially located feedback port in the rear of the fire chamber.
 14. The improved burner as claimed in claim 9 wherein said direct-air-supplying means supplies air to the region of the fire chamber adjacent the lateral plane in which the fuel inlet port is located.
 15. In a burner utilizing a fire chamber connected to a supply of fuel mixture from a pressure differential generator, a combustion gas feedback conduit for supplying heated combustion gases to the pressure differential generator to heat the fuel and a supply of pressurized air being applied to the pressure differential generator to deliver a fuel and air mixture to the fire chamber, the improvement comprising a burner having a fire chamber, said fire chamber terminating at an apertured front located wall, said wall having an exhaust gas outlet aperture sized to increase the back pressure in the fire chamber during burning operation, said fire chamber having a fuel inlet port located in a lateral side towards the rear of the chamber in a lateral plane to define a flame region in the rear of the fire chamber including the lateral plane, said feedback conduit being located to pass hot combustion gases from the rear of the flame region to the pressure differential generator for heating of fuel and means for supplying pressurized air directly to the fire chamber in the vicinity of the flame region and fuel inlet port to enhance fuel combustion and means located generally in the vicinity of the lateral plane to ignite the fuel.
 16. The improved burner as claimed in claim 15 and further including flue means for passing exhaust gases from the outlet aperture in heat exchange relationship with the air being supplied to the burner for preheating thereof. 